Labs filters drop-downs defaults initialisation

[pral2a]

Describe the bug
In /labs when clicking in Filter without setting the "Filter by country" and "Filter by status" drop-down it returns a rails exception.

It looks like the default behaviour of both drop-downs doesn't get properly initialised. When the drop-downs are selected, even if nothing is changed, defaults are set and the filter works properly.

To Reproduce
Steps to reproduce the behaviour A:

1. Go to /labs
2. Select a Country from the "filter by country" country drop-down
3. Do not touch / select any option in the "filter by country" nor "filter by status" drop-downs
4. Click on "Filter"
5. See error

To Reproduce
Steps to reproduce the behaviour B:

1. Go to /labs
2. Select a Country from the "filter by country" country drop-down
3. Do not touch / select any option in the status drop-down
4. Click on "Filter"
5. See error

Expected behaviour
Drop-downs should be properly initialised with defaults
When no country is selected it should return all the labs
When no country is selected but a status is set it should filter by status only, matching all countries
When no status is selected but a country is set it should filter by country only, matching all status

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Mac OS
• Browser Chrome
• Version 84.0.4147.89